It is known to provide an office chair having a back rest in which a flexible fabric cover is fitted onto a rigid frame to support the back of a user. The cover typically is formed of a mesh-like flexible material wherein the flexibility and resiliency of the fabric material serves to support and cushion the occupant's back. Separate padding or cushions are not provided and instead the chair back construction relies upon one or more exposed layers of the cover to resiliently support and cushion the occupant.
Office chairs with this type of back arrangement have relied upon various constructions for a back frame and cover material. It is an object of the invention to provide an improved frame and cover construction which overcomes disadvantages associated with prior chair constructions.
The invention relates to an office chair wherein the back construction comprises an internal multi-component frame and a fabric cover which covers the frame and supports the occupant's back in an open area of the frame.
More particularly, the back frame comprises laterally spaced apart rigid uprights which project upwardly from a seat assembly and define the contour and overall shape of the back. The frame includes a crossbar which defines a top edge of the back and has opposite ends which are removably engagable with the side rail. The crossbar is removable to permit fitting of a fabric cover on the side rails wherein the crossbar then is fitted into the cover into engagement with the side rails such that the fabric cover conforms to the crossbar and the side rails.
As to the fabric cover, the fabric cover includes a pocket at least at the upper edge thereof in which is received the crossbar. As such, the crossbar when engaged with the side rails is received within the pocket and pulled downwardly thereby. The cover further includes an attachment arrangement at the lower edge of the cover which is engagable with the back frame by first pulling the fabric cover tight and then engaging the cover to the chair. This tensions the fabric material such that the cover pulls downwardly on the crossbar and restrains the crossbar to prevent disengagement from the side rails.
The fabric cover may be formed as a sock that is hemmed on at least three sides and on a central portion of the bottom edge. The engagement structure in this arrangement comprises an attachment or retaining rod which inserts into the interior of the cover and nests within the lower hem wherein the opposite ends of the rod project outwardly of the sock and are engaged with the bottom of the back frame.
In a further embodiment, a single-layer cover or sock is provided which is hemmed about the periphery thereof to define tubular pockets along the sides and top edge and along a center section of the bottom edge. The pocket along the lower edge of the cover includes openings near the bottom corners to allow for an attachment or retaining rod to be fitted therethrough in the same manner as the multi-layer sock. To allow for fitting of the crossbar to the side rails, the upper edge of the hem also includes relatively small openings near the upper corners of the cover. First, one end of the crossbar is inserted into a corner opening, and then, the crossbar is slid entirely into the upper pocket. The opposite ends of the crossbar fit on the upper ends of the side rails such that the cover holds the crossbar in place. In this construction, it is preferable to provide an exterior trim assembly which clamps onto the upper edge of the cover and the crossbar to hide the crossbar and the corner openings.
With these arrangements, a fabric cover can be readily fitted onto the side rails of a back frame and a crossbar assembled in place. The crossbar thereby is held in place by the cover and the tensioning of the cover by the attachment rod. This provides for ready assembly and tensioning of the fabric material while improving upon the construction of the frame and simplifying the assembly process.
Other objects and purposes of the invention, and variations thereof, will be apparent upon reading the following specification and inspecting the accompanying drawings.
Certain terminology will be used in the following description for convenience and reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.